Rolling mill



1957 P. s. E. FREDRIKSSON 2,730,948

ROLLING MILL Filed Feb. 9, 1954 2 Sheets-Sheet 1 I M- ZZA 1957 P. s. E.FREDRIKSSON 2,730,943

ROLLING MILL Filed Feb. 9, 1954 2 ShGGtS-SI'ISG'I; 2

United States Patent ROLLING MILL Per Sven Engelbrekt Fredriksson,Vasteras, Sweden, as-

signor to Aktiebolaget Svenska Metallverken, Vasteras, Sweden, ajoint-stock company limited Application February 9, 1954, Serial No.409,145

Claims priority, application Sweden February 10, 1953 Claims. (Cl.80-14) The present invention relates to rolling mills of the socalledstep rolling or pilger type having a pair of cooperating, complementarygrooved die-rolls or rockers, which are brought in a commonreciprocation while being simultaneously turned about their axes toachieve an alternative constriction and widening of the space formed bythe grooves between the rollers.

Rolling mills of substantially the above kind are previously known,wherein the complementary rockers are journalled in a roller supportfurnished with projecting members, provided with wheels in such a waythat the support also constitutes a carriage, which in some way or otheris brought to perform a reciprocating motion, the complementary rollersturning to and fro about their respective axes.

A carriage of this kind will run with its wheels on a suitable bed.However, in step rolling mill apparatus known hitherto the carriage willbe very heavy due to its design, amongst others due to the fact that thewheels of the carriage are placed at a considerable distance from thespace between the rollers and that the drive for the carriage appliesforces in an unsymmetrical way in relation to said space, which willgive rise to oblique-setting moments, which also should be consideredwhen dimensioning the carriage. Due to the fact that the carriage thuswill obtain considerable dimensions it will consequently obtain a largemass and the mass forces being encountered at the changes of thedirection of motion will influence besides upon the carriage also uponthe dimensions of the driving members for the same, bulky and expensiveconstructions being the result.

The invention, the object of which is to obtain a general reduction ofthe dimensions and mass forces and to provide a reliable and smoothlyoperating step rolling or pilger type rolling mill, is essentiallycharacterized therein that the die-rolls or rockers, their geometricaxes one above the other, are journalled in bearing blocks and furthertherein that supporting or carrying wheels are arranged coaxially to theupper rocker which wheels alone carry the said bearing blocks androckers supported from essentially horizontal rails or races arrangedfor the carrying wheels so that said bearing blocks and rockers may bereciprocated as a carriage.

The invention will be more fully disclosed hereinafter with reference toan embodiment diagrammatically shown in the attached drawings and inconnection therewith further characterizing features of the inventionwill be set forth.

Figure l is a perspective view of a rolling mill of the step rolling orpilger type according to the invention.

Figure 2 is a vertical section through the rolling mill according toFigure l, the roller support or carriage and the complementary rollersor rockers journalled therein being shown in elevation.

In the embodiment of the step rolling mill according to the inventionshown in the drawing the roller support ice plementary die-rolls betweenthem. Both blocks are divided into two halves 1, 2 and 3, 4respectively, which are kept assembled by means of bolts 5 and nuts 6.The two upper block halves constitute bearings for a throughgoing rollershaft 7 and the two lower block halves constitute similarly bearings fora throughgoing roller shaft 8. The roller shaft 7 carries between theblock halves 1 and 3 a grooved die-roll 9 and the roller shaft 8 carriesbetween the block halves 2 and 4 a grooved die-roll 10. The grooves ofthe die-roll 9, which are three in number, are designated by 11, 12 and13 and correspond to three grooves 14, 15, 16 in the lower die-roll 10.Said grooves present a semi-circular cross section and form in couplescircular roller spaces or the like 17, 18, 19.

As will be evident particularly from Figure 2 the grooves taper alongthe periphery of the rollers similar to a wedge so that the rollerspaces 17, 18 and 19 are reduced or increased upon turning the pair ofrollers 9, 10 in order in known manner to render possible the reductionof tube or rod blank passed through the rolling mill.

Arranged on the roller shaft 7 outside the block are two runner wheels20 and 21, which at will may be fixedly or loosely mounted on saidshaft. Said runner wheels support the entire carriage, viz. the blocks,shafts and pair of rollers from two substantially horizontal lunnerrails 22 and 23, which are fixed to the main frame of the rolling mill,said main frame being designated by 24. When the carriage is broughtinto reciprocation the runner wheels 20 and 21 thus will run upon therunner rails 22 and 23.

. It is a requirement, however, that simultaneously with thereciprocation of the carriage, both rollers 9 and 10 proper comprisestwo separate blocks, which carry comshould be given a rotary motion, sothat the roller spaces 17, 18 and 19 are alternatively widened andcontracted. To this end the roller shaft 7 is provided with gears 25 and26 fixedly attached thereto, which cooperate with racks 27 and 28respectively, for the sake of expediency formed in the runner rail 22and 23 respectively. In a corresponding way the roller shaft 8 isprovided with the gears 29 and 30, which cooperates with racks 31 and 32respectively, which are also fixed to the frame 24. It should be notedthat both pairs of racks 27, 31 and 28, 32 respectively may be mutuallyadjustably displaced in a horizontal direction for the purpose ofadjusting the roller space and to provide for that the engagementbetween the teeth will be equal on both sides. Furthermore it may bementioned that the diameters of the runner wheels 20, 21, particularlyin those cases when they are rigidly attached to the roller shafts, arechosen so as to coincide with the pitch diameters of said gears.Furthermore it should be mentioned that the pitch diameter of the gearsand furthermore the diameters of the runner wheels are preferably chosenso that they will lie between the maximal and minimal pitch diameter ofthe roller groove in View of the varying pitch diameter for the latterat its engagement with the tube or rod blank being constricted in theroller space.

In accordance with Figures 1 and 2 on the shaft 7 at each of its ends aconnecting rod 33 and 34 respectively engages with a connecting rod end35 and 36 respectively, free on the shaft. In a corresponding way on theshaft 8 two connecting rods 37 and 38 engage with pivoted connecting rodends 39 and 40. The connecting rod 33 is by means of a connecting rodend pivotally supported from a gear 41 formed as a flywheel. Likewisethe connecting rod 34 by means of a connecting rod end 42 is pivotallysupported from a similar gear 43, gear 41 en gaging a similar gear 44and the gear 43 with a gear 45. The gear 44 by means of a connecting rodend not shown is connected to the connecting rod 37 and also the gear 45by means of a connecting rod end 46 to the connecting rod 38.

Rotation is imparted from a motor, not shown via V- belts or the like 47to a pulley 48 on a shaft 49 carrying two driving gears 50 and 51 inmesh with the gear 45 and 44 respectively.

When rotation is imparted to the pulley 48 both gears 50 and 51 aredriven and simultaneously the pairs of gears 44, 41 and 45, 43 are putin rotation to drive, through the connecting rods 33, 34, 37, 38, theblocks etc. and also the rollers 9 and 10 in a horizontal directionwhile simultaneously turning of the same to alternatively increase andconstrict the circular roller spaces 17, 18, 19, through which, in aknown manner, the tube or rod blanks are successively passed to obtain areduced cross section. In such connection it should also be mentioned,that it is preferable not to have the grooves in the rollers extendingthe entire periphery of the rollers. Care should namely be taken thatcertain portions of the periphery is le t free for the arrangement ofdescents or reduced portions, so that the blanks handled are gettingdisengaged from the rollers or rockers in the turning positions of thecarriage, while the blanks are advanced and turned respectively. Apreferred length of the groove corresponds in accordance with inventionto about 320 of the periphery of the roller or rocker.

As will be particularly evident from Figure l the connecting rods engageboth axes of the rollers in a symmetrical way in relation to the rollerspace and furthermore the carriage assemblage travels on a race, whichessentially coincides with the horizontal centre plane of the rollerspace, which is particularly important, since thereby theoblique-setting moments encountered in other known roller carriages instep rolling mills are eliminated. Furthermore it should be noted thatthe symmetrical arrangement of all of the connecting rods contributes tothe fact that the horizontal resultant of the forces transmitted by theconnecting rods remain in the plane of the roller space. As is evidentfrom the aforesaid in accordance with the invention it is aimed at asfar as technically possible to eliminate oblique-setting moments and toreduce weight of the roller carriage, whereby the mass forces may bereduced to such figures that the assemblages say be givencorrespondingly slender dimensions.

Although, in the embodiment shown, rollers having three grooves areshown, this does not exclude the utilization of roller having anotherdesired number of grooves.

The invention is not limited to the embodiment shown and described butmay be varied in several respects within the scope of the basicinventive idea.

Having now described the invention, what I claim as new and desire tosecure by Letters Patent, is:

l. A step rolling mill of the pilger type comprising a frame, spaced,parallel, substantially horizontal tracks on said frame, a pair ofcooperating, complementary, grooved rollers, bearing blocks rotatablymounting said rolls in operative relationship, said rolls being disposedone above the other, a roll shaft extending from each end of each rollbeyond said bearing blocks, a wheel mounted on each end of the upperroll shaft outwardly of said bearing blocks and engaging said tracks toreciprocably support said rolls and said bearing blocks, a gear fixed oneach end of said upper roll shaft outwardly of said wheels, spaced,parallel racks carried by said frame and engaging said gears, 21 secondgear fixed on each end of the lower roll shaft outwardly of said bearingblocks, spaced, parallel racks carried by said frame and engaging saidsecond gears, a connecting rod rotatably secured to each end of eachroll shaft outwardly of said first and second gears and crank meansconnected to said connecting rods whereby upon operation of said crankmeans, said rolls and said bearing blocks will be reciprocated as a unitalong said tracks and maintained in upright position by said connectingrods, the engagement of said gears with said racks causing simultaneousrotation of said rolls.

2. A step rolling mill of the pilger type comprising a 42 frame, spaced,parallel, substantially horizontal tracks on said frame, a pair ofcooperating, complementary, grooved rolls, bearing blocks rotatablymounting said rolls in operative relationship, said rolls being disposedone above the other, a roll shaft extending from each end of each rollbeyond said bearing blocks, a wheel mounted on each end of the upperroll shaft and engaging said tracks to recipro'cably support said rollsand said bearing blocks, a gear fixed on each end of said upper rollshaft outwardly of said bearing blocks, spaced, parallel racks carriedby said frame and engaging said gears, a second gear fixed on each endof the lower roll shaft outwardly of said bearing blocks, spaced,parallel racks carried by said frame and engaging said second gears, aconnecting rod rotatably secured to each end of each roll shaftoutwardly of said first and second gears and crank means connecting tosaid connecting rods whereby upon operation of said crank means, saidrolls and said bearing blocks will be reciprocated as a unit along saidtracks and maintained in upright position by said connecting rods, theengagement of said gears with said racks causing simultaneous rotationof said rolls.

3. A step rolling mill of the pilger type comprising a frame, spaced,parallel, substantially horizontal tracks on said frame, a pair ofcooperating, complementary, grooved rolls, bearing blocks rotatablymounting said rolls in operative relationship, said rolls being disposedone above the other, a roll shaft extending from each end of each rollbeyond said bearing blocks, a wheel mounted on each end of the upperroll shaft and engaging said tracks to reciproc'ably support said rollsand said bearing blocks, a gear fixed on each end of said upper rollshaft outwardly of said bearing blocks, spaced, parallel racks carriedby said frame and engaging said gears, a second gear fixed on each endof the lower roll shaft outwardly of said bearing blocks, spaced,parallel racks carried by said frame and engaging said second gears, aconnecting rod rotatably secured at each end of each roll shaftoutwardly of said first and second gears reciprocating means connectedto said connecting rod whereby upon operation of said reciprocatingmeans said rolls and said bearing blocks will be reciprocated as a unitalong said tracks and maintained in upright position by said connectingrods, the engagement of said gears with said racks causing thesimultaneous rotation of said rolls.

4. A step rolling mill of the pilger type comprising a frame, spaced,parallel, substantially horizontal tracks on said frame, a pair ofcooperating, complementary, grooved rolls, bearing blocks rotatablymounting said rolls in operative relationship, said rolls being disposedone above the other, a roll shaft extending from each end of each rollbeyond said bearing blocks, a wheel mounted on each end of the upperroll shaft and engaging said tracks to r'eciprocably support said rollsand said bearing blocks, a gear fixed on each end of said upper rollshaft, spaced, parallel racks carried by said frame and engaging saidgears, a second gear fixed on each end of the lower roll shaft, spaced,parallel racks carried by said frame and engaging said second gears, aconnecting rod rotatably secured to each end of each roll shaftoutwardly of said first and second gears and reciprocating meansconnected to said connecting rods whereby upon operation of saidreciprocating means said rolls and said bearing blocks will bereciprocated as a unit along said tracks and maintained in uprightposition by said connecting rods, the engagement of said gears with saidracks causing simultaneous rotation of said rolls.

5. A step rolling mill of the pilger type comprising a frame, spaced,parallel, substantially horizontal tracks on said frame, a pair ofcooperating, complementary, grooved rolls, bearing blocks rotatablymounting said rolls in operative relationship, said rolls being disposedone above the other, a roll shaft extending from each end of each roll,a wheel mounted on each end of the upper roll shaft and engaging saidtracks to reciprocably support said rolls and said bearing blocks, agear fixed on each end of said upper roll shaft, spaced, parallel rackscarried by said frame and engaging said gears, a sec- 0nd gear fixed oneach end of the lower roll shaft, spaced, parallel racks carried by saidframe and engaging said second gears, a connecting rod rotatably securedto each end of each roll shaft and reciprocating means connected to saidconnecting rods whereby upon operation References Cited in the file ofthis patent UNITED STATES PATENTS 2,436,098 Coe Feb. 17, 1948

